A make-up artist for KISS frontman Gene Simmons has filed a lawsuit against the rock star, claiming that he sexually assaulted her!

Victoria Jackson describes in her suit that she was working a concert at the ESPN Sports Center in November when Simmons, dressed in his costume, approached her and said in "a lecherous and inappropriate manner, 'I like you.'"

He then reportedly grabbed her, and although she responded "Ouch. You are hurting me," because the spikes in his chest were jabbing her, he "pulled her even closer, tightly, pinning her arms and said, 'No, not yet"…the defendant "started humping her…to the extent that she could feel his groin grinding into her."

WTF?! Why the eff would he hump her?? Gross!

After he apparently 'finished,' he said "Aw, that's better! Now you can go."

Jackson claims there were witnesses who can support her claims, and is seeking $500k in damages for having suffered humiliation, shame, embarrassment, anger, anxiety, loss of sleep and depression.

Simmons denies the allegations and has fired a countersuit against Jackson.

Wow! Pretty HOriffic - and bizarre - if it actually happened! What do U think?? Do Jackson's claims sound legit??